Snow depth variability increases in a marginal snowpack as it transitions from accumulation to melt

Mountain snowpacks in the southwestern US often lack representative data needed to improve water budget forecasts. This research measures the variability of a marginal snowpack in New Mexico to better understand snow depth distribution and estimate snow water equivalent (SWE). A 1,200 m2 survey plot was established in the Sandia Mountains. Snow depth across a forest stand boundary was compared for the 2019 and 2020 winter seasons to evaluate spatial and temporal variability. During 2019, maximum snow depth (148 cm) was observed on March 8 and peak SWE (338 mm) on March 21. In 2020, maximum depth (125 cm) and peak SWE (254 mm) were both observed on February 25. A ripening period was identified between the accumulation and melt periods, where spatial variability increased over time until the maximum was reached during the melt period. One transect per 100 m2, or approximately one depth point per 20 m2, achieved a representative depth observation for both seasons. The forested area contributed to snow persistence as well as interannual depth variability, with the greatest variability observed along the forest stand boundary. A better understanding of snowpack distribution in these water-stressed regions will improve runoff forecasts and water management decisions.